1. Field of the Invention.
The present invention relates to positive pressure ventilation, and more particularly to a new and improved method and apparatus for providing positive pressure ventilation on a large scale.
2. Description of the Prior Art
Positive pressure ventilation is a fire fighting technique which is used to remove smoke and provide ventilation to burning structures. Small scale portable blowers such as that disclosed in U.S. Pat. No. 4,906,164 have been designed to be able to quickly evacuate smoke from a burning building. This decreases the potential for smoke damage, and improves visibility and breathing for fire fighters so that they may more efficiently and safely fight the fire.
Larger scale blowers have been developed for fighting outdoor grass or forest fires, such as those disclosed in U.S. Pat. Nos. 1,849,411 and 1,871,096. However, these inventions provide only a general flow of air, and usually accomplish little more than moving smoke away from a small area. Similar devices have been developed for suction of smoke and hot air from burning buildings, such as those described in U.S. Pat. Nos. 1,351,700 and 1,926,298. However, these devices can be severely damaged by the constant flow of smoke and hot air that passes through them.
A mobile wind-generating machine has been developed for use in creating a large-volume stream of air for blowing back forest fires, providing evaporation in orchards, and/or simulating storms on a motion picture set in U.S. Pat. No. 3,128,036. However, this wind-generating machine suffers from several drawbacks which prevent it from optimal use in positive pressure ventilation. Among other things, the machine is powered by an internal combustion engine which is located directly in the path of the incoming air to the machine. This location tends to disrupt and restrict the flow of air through the machine. An internal combustion engine also severely limits the maximum speed as well as the range of speeds of the blower, thereby limiting the output airflow. Also, while the flow of air through the machine is streamlined, the output is not concentrated in a conical shape as preferred in positive pressure ventilation.
In the event of a vehicle fire, gas leak or terrorist attack occurring in the middle of a large structure such as a tunnel, the positive pressure ventilation fire fighting technique calls for blowing a large volume of air into one end of the tunnel to force the smoke and hazardous gasses out through the other end, or through ventilation ports. This allows the fire fighters to enter the tunnel at the entrance where the blower has been deployed with the wind at their backs, enabling them to easily see and extinguish the fire and to locate survivors. A small blower would be inadequate to move the required volume of air, and there is no large scale blower particularly adapted to accomplish the needs of positive pressure ventilation (e.g. compensating for any inclination of the road leading to the tunnel, etc.). In particular, existing blowers do not provide a sufficiently wide range of positioning adjustability or air velocity adjustability, S nor do they concentrate a sufficient amount of air in the desired conical shape in order to completely cover the tunnel entrance for positive pressure ventilation.
The present invention is a large scale positive pressure blower designed to provide positive pressure ventilation of large (enclosed) spaces such as tunnels, mines, halls, warehouses, large Box stores, high-rise buildings, shopping malls and the like. In accordance with the invention, a hydraulically or electrically operated ventilation blower is provided on an adjustable elevation device that may be mounted either on a movable vehicle or trailer, or in a stationary location in the vicinity of structure openings or portals. The vehicle or trailer mounted embodiment of the invention may be made available on a scaffold, scissor lift, telescopic lift, hydraulic lift or other suitable elevating device, allowing for simple and easy vertical positioning of the blower.
The blower has a generally cylindrical overall configuration, and is pivotally mounted to and supported by a pair of arms, one on either side, allowing the blower to be tilted up or down over a horizontal axis. The support arms are attached to a rotatable swivel mount, allowing the blower to be rotated in a circular arc around a vertical axis. This pivotal support of the blower on a rotatable mount provides a wide range of different positioning alternatives for the blower, allowing the output airflow to be aimed in a precise direction in order to optimize use in a positive pressure ventilation situation.
The blower produces a conical stream of air which is designed to be aimed towards a portal or opening in a space to be ventilated (such as a transportation tunnel) and which completely covers the opening. Such complete coverage is necessary in order to accomplish the objective of positive pressure ventilation by forcing the air inside the space to exit through another, different opening (e.g. the other end of the tunnel), and preventing it from returning back through the air flow entrance.
Inside the cylindrical blower housing or shroud, a plurality of adjustably angled blades or vanes are provided in radial relationship to a rotatable center. Rotation of the center and blades forces air through the cylinder. The center and the blades are designed for extremely high rotation speeds in order to generate very large volumes of moving air. In the preferred embodiment, this rotation is provided hydraulically thereby providing an infinitely variable speed control of the blower. Hydraulics may also be used to operate the lift, swivel and pivot for positioning the blower. In such a case, a single hydraulic system may be used to control all of these moving parts. Alternatively, the blower may be powered using a conventional electric or fuel powered motor using either direct or belt drive.
In alternative embodiments, the blower cylinder may be equipped with one or more of the following attachments: (1) water spray nozzles which enable the blower to be used to cool objects, extinguish fires, and secure task forces; (2) water mist emitters which allow water vapor to be mixed with the air stream flowing from the blower (fog) for the same purposes as the nozzles; and/or (3) illumination apparatus for use under low visibility or at night.
In the vehicle or trailer mounted embodiment, the swivel support is attached to a vertical lift which may also be powered by the same hydraulic system as the other hydraulically operated parts. In this embodiment, the vehicle or trailer is transported to a location outside the area to be ventilated. The blower is raised by the lift to a suitable height, and is then adjusted using the horizontal tilt and rotatable swivel for precise positioning of the blower in order for the air stream to completely cover an opening in the space to be ventilated.
The stationary embodiment of the invention is designed to be attached to a mount near an opening in a large area that may require positive pressure ventilation in the event of a fire. For example, the invention may be attached to a mount on the outside of a tunnel portal. The blower in this embodiment uses the same cylindrical structure pivotally mounted on a rotatable swivel as described above. The swivel, in turn, is attached to a mount having the ability to raise and lower the blower in order to properly position it in front of the opening for positive pressure ventilation, and to move it aside when not in use. Such positioning may be accomplished in a variety of ways, including a movable boom, a sectional or elbow lift, a crane, a knuckle arm, a scissor lift, a telescoping lift or the like.
A plurality of blowers may be employed to provide a sufficient volume of air to evacuate a large building such as an aircraft hangar. In such a situation, the air flow from each of the blowers is directed at a single building entrance. Such blowers may be placed side by side to provide broad coverage to the building entrance, one in front of another to increase air velocity, or both for both effects. One or more stationary (i.e. non-vehicle mounted) blowers may be fixedly placed near the entrances of such buildings for preventative purposes where the need for positive pressure ventilation may arise.
The conical air flow of the blower is formed through the interaction of the cylindrical housing and the rotating blades therein. The longer the distance between the blades and the exit from the housing the more narrow and more focused the cone of exiting air. Increasing the RPM of the blades also forms a better cone of air for direction at an opening in the structure.
It is therefore a primary object of the present invention to provide a portable positive pressure ventilation blower for use in fighting fires associated with large structures such as tunnels, mines, halls, warehouses, large Box stores, high-rise buildings, shopping malls and the like.
It is also an important object of the invention to provide a positive pressure ventilation blower which is capable of delivering a large volume of air over a widely variable velocity range using a specially designed hydraulically driven blower system.
It is a further object of the present invention to provide a portable positive pressure ventilation blower which is capable of delivering a large volume of air in a concentrated stream having a conical shape in order to provide ventilation on a very large scale.
It is a further object of the present invention to provide a portable positive pressure ventilation blower which may be positioned over a wide range of alternatives, allowing the output airflow to be aimed in a precise direction in order to optimize use in a positive pressure ventilation situation.
It is another object of the present invention to provide a stationary positive pressure ventilation blower for available use in fighting fires that is mounted near an entrance to a large structure such as a tunnel, mine, hall, warehouse or the like.
It is another object of the present invention to provide a stationary positive pressure ventilation blower equipped with spray nozzles and/or mist emitters for use in cooling objects, extinguishing fires, and assisting fire fighting forces.
Additional objects of the invention will be apparent from the detailed descriptions and the claims herein.